Doctoral Dissertations

Keywords and Phrases

blasting; downwash; gas emissions; gas monitor; UAV


"This research concludes that the downwash region of a rotary-wing unmanned aerial vehicle (UAV) does not produce pressure variations substantial enough to cause significant changes in density-based gas concentration measurements. US regulations evaluate gas concentration as a function of gas density, and accurate concentration measurements are critical for protecting health and safety, which means evaluation of actual downwash effects on measured gas concentration is essential.

During experimentation, the UAV was fixed to a stand in a sealed chamber filled with NOx (NO and NO2) of constant concentration. The UAV rotors ran at hovering speeds, and gas concentrations were measured at various locations around the UAV. NOx was chosen due to intended US regulations on surface mine blasting NOx emissions, though the results should be applicable to most emissions of interest that are monitored by a UAV system. All variables other than the presence of downwash were held constant or accounted for, so the only source of concentration variation would have been caused by pressure changes in the downwash region. No significant variations were observed, providing evidence that downwash pressure variations are not substantial enough to alter density-based gas concentration measurements.

Numerous researchers have suggested that downwash may affect gas concentration measurements, though no researcher has previously isolated and defined the effect. This dissertation’s findings allow researchers to safely assume this source of previously undefined error is statistically negligible, provided the UAV and gas sampling point are located entirely within the gas cloud and the downwash region has stabilized"--Abstract, p. iii


Johnson, Catherine

Committee Member(s)

Burken, Joel G. (Joel Gerard)
Harrison, William A.
Perry, Kyle A.
Worsey, Paul Nicholas


Mining Engineering

Degree Name

Ph. D. in Explosives Engineering


Missouri University of Science and Technology

Publication Date

Spring 2023


xii, 119 pages

Note about bibliography

Includes_bibliographical_references_(pages 107-118)


© 2023 Jacob Lane Brinkman, All Rights Reserved

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 12242

Electronic OCLC #